※ 글의 내용과 일치하지 않는 것을 고르시오. [문 17 ～ 문 18] We dream during the REM (rapid eye movement) stage of sleep. We have about five periods of REM sleep during the night. The first REM cycle lasts about 10 minutes. As the night goes on, the REM cycle gets longer. By early morning, the REM cycle can last up to 90 minutes. Usually, it is in this last REM cycle that we remember our dreams. Dreams change as people become older. Babies dream about half of the time they are asleep. At age eight or nine, children start to tell their dreams as stories. People in their 20's and 30's say that many of their dreams are about feeling guilty for things that they did. Older men usually dream about work or their families.